Film production technologies are frequently used in production of displays such as formation of semiconductive layers. Particularly the film production technology using an ink jet device (ink jet method) is employed in production of organic EL layers for organic EL elements, color filter layers for color filter substrates, and functional thin films such as pattern wirings for metal wiring substrates. The ink jet method makes it possible to easily adjust the thickness of thin films and easily respond to enlargement of the area compared to solid phase methods such as deposition. Further, the ink jet method provides high material efficiency, and thus makes it possible to reduce the cost.
Generally in the ink jet method, a functional fluid containing a functional material (thin film material) and a solvent is applied and then the solvent is removed to leave a functional thin film. If the solvent volatilizes at the head portion and thereby a functional material or the like is precipitated during ejection of the printing liquid droplets, ejection defects may occur such as that the droplets maybe ejected onto different positions or the amounts of ejected droplets may be different. Further, depending on the differences in the ejection accuracy or the ejection amount of the nozzles of the ink jet device, functional thin films having desired film thicknesses may not be achieved or the film thicknesses of the functional thin films may be different.
The ink jet method thus usually employs a process of applying a functional fluid to regions partitioned by portions called banks. For example, Patent Document 1, discloses a technology of filling a functional fluid in the regions partitioned by banks and forming patterned wirings. This technology requires the banks to be formed corresponding to the wiring patterns, and thus still has room for improvement in that it is difficult to form, with this technology, complicated wiring patterns or high resolution devices. Meanwhile, Patent Documents 2, and 3, each disclose a technology of stacking lyophilic bank and a lyophobic bank. As for this technology, there is room for improvement in that when a surface treatment is performed on the bank stacked on the upper side, the effect of the bank arranged thereunder is negated, and thus sufficient effects cannot be provided. Patent Document 4, discloses an organic EL display device in which an organic EL layer is formed in a region partitioned by stacked lyophilic first bank and a lyophobic second bank. In this technology, there is room for improvement in that an electron injection transport layer cannot be completely covered by a middle layer and a light-emitting layer, which are to be applied on the electron injection transport layer, because the electron injection transport layer is attached on the wall surface of the banks or on the banks, and the incomplete covering causes a direct contact between the electron injection transport layer and the cathode, whereby the functions of the organic EL layer decrease.    [Patent Document 1]    Japanese Kokai Publication No. 2007-95729    [Patent Document 2]    Japanese Kokai Publication No. 2007-280866    [Patent Document 3]    Japanese Kokai Publication No. 2008-4376    [Patent Document 4]    Japanese Kokai Publication No. 2005-326799